- weak battery/alternator
- not checking tire pressure when the air temp has dropped 30 degrees C since you last filled them
- not using the proper oil weight for the conditions... Many cars suggest 5W-30 in the winter if they use 10W-30 in the summer. Check owners manual
- not using the proper grade of gasoline... If a vehicle requires 91+ octane, some people get away with running 89 in the summer. In the winter when the air is more dense, you could get pre-ignition or detonation and start doing damage...